Electric scalpels are employed widely as surgical devices. An electric scalpel is an instrument which, by passing a high-frequency current of from several hundred kilohertz to several megahertz at a power of several hundred watts into an electrode at the slender scalpel tip of its distal end, is used instead of a knife to make an incision and coagulate tissue. When the electric scalpel is employed for the coagulation and hemostasis of tissue, the high-frequency current is passed into the tissue, which has been contacted by the scalpel tip electrode, in concentrated fashion at a single point, whereby the protein in the tissue is coagulated and desiccated by Joule heating produced in the tissue.
Since the scalpel tip electrode is contacted with the tissue when the electric scalpel is used for coagulation and hemostasis, the coagulated tissue tends to adhere to the scalpel tip electrode and peel off, as a result of which the tissue is damaged. An electric scalpel having a spray coagulation function is available as an electric scalpel that is capable of achieving non-contact coagulation and hemostasis. By applying a high voltage (on the order of twice that applied in the ordinary electric scalpel) to electrodes, this electric scalpel coagulates tissue by irradiating the tissue with an arc discharge under conditions in which the electrodes are held several millimeters away from the tissue in air. However, since the discharge is effected in highly insulative air, control of the arc discharge is difficult, more current flows than is necessary and excessive coagulation and tissue carbonization readily occur. An argon beam coagulator has been proposed in Japanese Patent Laid-Open Publication No. 62-240043 in order to solve this problem. According to this art, an opposing electrode plate 80 is affixed to a living body 50, as shown in FIG. 6, and the living body 50 is held at the same potential as that of the opposing electrode plate 80. A pencil-shaped device 110 is then supplied with argon gas from a gas supply unit 120 and an electrode 116 provided on the pencil-shaped device 110 is supplied with high-frequency current from a control unit 130. As a result, an arc discharge is produced from the electrode 116 to the living body 50 held at the same potential as that of the opposing electrode plate 80 and argon gas ionized by the arc discharge is jetted toward the body so that a high-frequency current is introduced into the tissue in non-contacting fashion as an arc discharge in argon gas, whereby coagulation and hemostasis of the tissue are achieved. Since the ionized argon gas possesses conductivity, this method is such that a stable arc beam can be emanated toward the tissue so that uniform coagulation is possible with little energy.